Self-regulating electric steam generator



1948- R. w. E. VICKERY 2,447,294

SELF-REGULATING ELECTRIC STEAM GENERATOR Filed Feb. 20, 1946 e Sheets-Sheet 1 mewar zeal viz,

Aug. 17, 1948. I w, VICKERY 2,447,294

SELFREGULATING ELECTRIC STEAM GENERATOR Filed Feb. 20, 1946 6 Sheets-Sheet 2 Aug. 17, 1948. R. w. E. VICKERY 2,447,294

SELF-REGULATING ELECTRIC STEAM GENERATOR Filed Feb. 20, 1946 5 Sheets-Sheet 5 Aug. 17, 194s.

R. w. E. VICKERY SELF-REGULATING ELECTRIC STEAM GENERATOR Filed Feb. 20, 1946 6 Sheets-Sheet 4 Aug. 17, 1948. R. w. E. VICKERY 2,447,294

SELF-REGULATING ELECTRIC STEAM GENERATOR Filed Feb. 20, 1946 6 SheetsSheer, 5

Patented Aug. 17, 1948 SELF-REGULATING ELECTRIC STEAM GENERATOR Ralph W. E. Vickery, Brockton, Mass.

Application February 20, 1946, Serial No. 648,977

15 Claims. 1

This invention relates to an electric steam generator of the type illustrated in Patent No. 1,862,- 071, granted to me June 7, 1932.

The principal objects of the invention are to provide a reliable and efiicient electric steam generator which is automatically self-regulating; to provide a steam generator which is designed to meet the several public safety requirements, both with respect to electrical and mechanical hazards; to provide an apparatus which is adapted for a wide variety of uses requiring operating pressures which may vary from a few pounds to several hundred pounds; and to provide an apparatus which is of relatively simple design and which can be manufactured at a relatively low cost without the use of skilled workers.

Further objects relate to various features of construction and will'be apparent from a consideraticn of the following description and the accompanying drawings, wherein- Fig. l is an elevation, with parts broken away and shown in section, of one embodiment of the invention particularly suitable for use with sterilizers, cookers and other apparatus having a relatively steady demand and low steam consumption;

Fig. 2 is an exploded view of a preferred form of electrode;

Fig. 3 is a side elevation, partly in section, of another embodiment of the invention;

Fig. 4 is an enlarged sectin through one of the insulating coupling members;

Fig. 5 is an elevation, partly in section, of another embodiment of the invention applied to a water heating device;

Fig. 6 is a front elevation of another embodiment of the invention particularly suitable for use in connection with installations having a relatively high steam consumption;

Fig. 7 is a side elevation of the apparatus shown in Fi 6;

Fig. 8 is a top plan view of the apparatus;

Fig. 9 is an enlarged section on the line 9.9 of Fig. 6;

Fig. 10 is a sectional view of a preferred form of a trap; and

Fig. 11 is an elevation of a float switch and associated parts which may be substituted for the float valve and associated parts shown in Figs. 6 to 8.

In accordance with the present invention my improved steam geen-rator comprises a plurality of electrodes which may be mounted within a suitable casing or housing, or one of the electrodes may of itself provide a casing, but in any event the electrodes.

the electrodes are suitably insulated from each other and define a steam-generating chamber having fluid inlet and outlet lines respectively connected with the lower and upper parts of the chamber. The number and arrangementof electrodes may vary, depending upon the type of alternating current to be employed, and for general use, I prefer tubular electrodes telescopically disposed and suitably insulated from each other with the annular space between the outer face of the inner electrode and the inner face of the outer electrode defining the steam-generating chamber or zone.

The outlet and inlet lines may be directly connected by a suitable conduit, a supply tank, a steam-consuming apparatus, or any other means which with the inlet and outlet lines provides an exterior fluid circuit between the upper and lower parts of the steam-generating chamber. The outlet line may provide or be connected with a steam discharge line, depending upon theparticular construction, and the inlet line is connected or associated with means for admitting water or electrolyte to a predetermined initial fiuid-level within the steam-generating chamber above the lower parts of the electrodes and at a level greater than that required for normal operation of the apparatus. To this end the inlet line may be connected with a conventional float valve associated with a water supply, or a tank, reservoir or the like adapted to supply water to the required level. Means are also provided to eliminate excessfluid in the form of vapor or liquid after a predetermined operating pressure has been reached, so as to reduce the fluid content of the chamber to a level below the initial fluid-level, but above the minimum level which permits the passage of an electric current through To this end a vapor blow-oft valve may be connected either in the outlet line or the inlet line, or the latter may be so designed. as to permit such excess fluid to back into a reservoir, tank or the like.

A pressure-regulating valve is connected in the fluid circuit, preferably in one of the lines and is operable to close the line when a predetermined pressure within the chamber is reached, thereby effecting an automatic regulation of the apparatus in the manner presently to be described. Water or electrolyte in the steam-generating chamber at or above the initial fluid-level is heated up by the passage of the alternating current therethrough, and when boilingoccurs, the pressure starts to build up. When the pressure reaches the point for which the regulating valve is set, the latter closes, although the pressure may continue to build up to a few pounds in excess of that for which the regulating valve is set. The pressure thus produced is effective either to operate the blow-01f valve or back excess fluid into the inlet line, depending upon the particular design of the apparatus, but in either case sufficient fluid is discharged or consumed to reduce the fluid-level to a point below the initial fluid-level, but above the minimum level necessary to maintain contact with the electrodes. As the fluidlevel decreases, the current consumption isr'reduced correspondingly so that by the time "the minimum operating level is reached, the current consumed and consequently the amount of'steam generated is merely that necessary to maintain the operating pressure and compensate for heat losses. Since at least a part of the electrodesare at all times emerged in the electrolyte, it might seem that the pressure would nevertheless continue' to build up in the absence of unusual heat losses. However, it has been observed that the upper part of the electrolyte which would normally: surround" the lower part of the electrodes is in the form of amass of froth or bubbles of reducedelectrical conductivity and functions to reduce the current consumption to a minimum. If the. pressure within the chamber drops below the operating pressure for'which the regulating valve isiset; the; latter opens sufficiently to permit or cause'enoughfluid to be admitted'into the chamber to raise the liquid level and the superposed froth-like mass, thus increasing the overall conductivityof the fluidwithin the chamber with a consequent increase in current consumption and generation of steam, until the aforementioned normaloperating pressure is again reached.

-When' the steam discharge line is open, there is of course a slight drop in pressure within the L chamber; and hence the regulating valve immediatelyopens to permit or cause more fluid to enter the chamber thus effecting an increased generation of steam until normal operating pressure is again established, whereupon the generation of steam is reduced to an amount equal to the steam output plus that necessary to compensate for heat losses. Thus, by a'simple manipulationof-the regulating valve, thesteamgenerator maybe set so'asautomatically to maintain a desired operating pressure for any output reasonably within. the capacity. of theapparatus.

.Referring to Figs. 1 and 2, the embodiment shown therein comprises a tubular casing .I, such asa length of. two-inch standard. pipe, the ends of-which are, provided with caps 2 and3. The upper, part. of the casing l is connected with. a fluid outlet line 4 and its lower part is connected with afluid inlet line 5.

Mounted coaxially within the casing I and welded,'brazed or otherwise suitably secured. to the inner face of the cap 3 so as to provide a good electrical contact, is an upstanding tubular outer electrode 8, the upper end of which terminates'below the inlet line and the sidewall of which is formed with a'plurality of spaced openings9. An inner electrode '10, depending from thecap 2, is telescopically disposed within the outer electrode 8 with its lower end terminating above the inlet line anddefining an annular steam-'generating-chamber within the casing l.

The electrode Ill, as shown in Fig. 2, comprises a tubular member or pipe H, the lower end of which carries" a porcelain insulating sleeve l2, and

its upper end is providedwith an opening I 4. The

Iii.

parts.

upper part of the electrode is rigidly secured to but insulated from the cap 2 by an assembly which projects through an opening in the cap 2. The insulating assembly comprises a screwthreaded bushing [5, the upper face of which carries an asbestos washer or gasket I5 and a generally conical insulator H. An asbestos washer l8 and another conical insulator I!) are disposed against the lower face of. the bushing l5 and a porcelain "sleeve extends through these A threaded stud 2| extends through the sleeve 20 and a small asbestos washer 22 into a metal bushing i24,:the lower end of which has a r pressed fit within the upper end of the electrode tube ll so. as toprovide a good electrical connection therewith. A nut 25 and lock washer 26 car- .ried bytheuupperend of the stud hold the parts in assembled relation, the threaded upper end of thestud 2| carrying a clamping screw 28 (Fig. 1) and thus provides a terminal or binding post to which one of apair of single phase alternating current power lines 30, 32 isconnected. IA switch 3! is connected in the power line 30, and the power line 32 is connected in any suitable manner with the cap 2 and is also grounded, as illustrated.

'The' outlet line' 4 is connected by a T or Y 35 with a pipe 36 which in turn is connected-with the upper port of aconventional float valve 38. The lower'or'dischargeport of the float valve is connected' by pipe 40 and elbow 4| to one sideof a pressure-regulating valve 42, the other side of which isconnected to the inlet line 5. The pressure regulatingvalve-GZ may bew'of conventional design and construction, such as an Acme regulating'valvepand is preferably provided with an index finger and-dial-43- designed to show the pressure for which the operating spring is set.

.The inlet 'line to the float valve 38 is connected through a shut-oif valvee45-to a service line 46 or other suitable source of water supply. The pipes 4, 36, and 5; together with the included float and pressure-regulating'valves, provide an exterior fluid circuit between the top part of the casing hand its lower part, which circuit is open so longasthe pressure therein-is below that for which the regulating valve 42 is set.

A pressure gauge 48 may be connected to the Y -35 and a steamdischargewline 50 is connected to the outlet-dined, the line:=50 belng provided With'a shut-offvalve 5! and-a-branch 52' which carries a safety valve E i-normally set to-pop or open at a pressure slightly greater than that for which the pressure-regulating valve 42 is set.

The construction and arrangement of parts are such that the float valve 38 is positioned to admit water into the casing l or steam-generating chamber to a predetermined initial fluid-level somewhat .in excess of that required for normal operation, and it will be observed that-in this particular embodiment the safety valve 54- is directly connected with the outlet 4 so that excess fluid in the form of steam or vapor maybe eliminated when the specified pressure is reached.

pressure, that the valve 54 is set to pop at 18 pounds per square inch pressure, that valves 45 and 5| are closed, and that switch 3| is openthe valve 45 is first opened to admit water through float valve 38, pipe 40, regulating valve 42 and line 5 into the casing I. When the water level in the casing I reaches the level of the float valve 38, the latter shuts off the water and the switch 3! may now be closed. The current passing through the water about the electrodes 8 and I heats the water and soon causes it to boil thus building up pressure within the system. It will be observed that since the circuit through the pipe 4, 36, 40 and is open, pressure throughout the system is equalized, but after the pressure reaches pounds per square inch. the regulating valve 42 closes and the pressure then continues to climb slightly until the safety valve operates to relieve the excess pressure, or the valve 5| is manually opened to consume the steam thus generated. If desired, blowing off the excess fluid may be accomplished by manual manipulation of the safety valve 54, but inany case the excess vapor is discharged with a corresponding decrease in the fluid-level about the electrodes, thus conditioning the apparatus for normal operation. Should the pressure tend to climb up, the valve 54 operates further to eliminate excess fluid so that ultimately the fluidlevel in the casing is reduced to a point where the current consumption and consequent generation of steam is the minimum necessary for maintaining a pressure of 15 pounds. When it is desired to utilize the steam. the valve 5| is opened and consequently a slight drop of pressure within the casing takes place, whereupon the regulating valve 42 opens sufficiently to admit enough water into the casing I to increase the fluid-level about the electrodes with a consequent increase in the rate of generation of steam until the pressure again reaches 15 pounds at which point the regulating valve closes the inlet line 5. The operation thus continues indefinitely so long as the consumption of steam is Within the capacity of the apparatus.

It will be noted that the rate of generation of steam is governed by the fluid-level about the electrodes and this level varies in accordance with the demand. If the demand drops, the prevailing pressure is nevertheless maintained and hence the regulating valve remains closed, thus preventing admission of water into the casing I. Since no water is being admitted to compensate for the steam consumed, the fluidlevel about the electrodes is reduced and as the fluid-level drops the power consumption likewise drops until it reaches the minimum. Thus, the apparatus is automatically regulating at the specified pressure for which the valve 42 is set throughout its rated capacity.

The embodiment shown in Figs. 3 and 4 is the same in principle as that shown in Fig. 1, but is designed for .use where there is no available water supply line. In this embodiment the outer electrode 8 constitutes the casing and hence its upper part is directly connected with the outlet line 4 and its lower part is connected with inlet line 5. The opposite ends of the electrode 8 are provided with caps 2 and 3, the cap 2 supporting the inner electrode H) which has the same construction as the inner electrode of the embodiment of Fig. 1, and power lines 38, 32 are connected with the electrodes, as shown.

The outlet 4 is connected through an insulating coupling 60, pipe 61, trap 62 and pressureregulating valve 64 with the upper part of a water supply tank or reservoir 65, and the inlet line 5 is connected through another insulating coupling with the lower part of the tank 65. The regulating valve 64 is the same type as that described in connection with the embodiment of Fig. 1 and may also be provided with a dial and index to indicate the pressure for which it"is set. The tank is provided with a cock 68 which may not only be used for filling the tank to the desired level, but also provides means for determining the maximum fluid-level within the electrode chamber 8 The upper end of the tank 65 may also be provided with a safety or blow-01f valve l8 and a pressure gauge 'H and the entire apparatus may be so constructed as to provide a portable unit.

The inner end of the trap 62 is connected with a steam discharge line '12 which may be provided with a shut-off valve 14 and the power line 30 may include the usual operating switch 3|, it being understood that the power lines 30, 32 are connected with a suitable source of alternating current such, for example, as a 220 volt, 60 cycle single phase transmission line or generator.

The insulating couplings 68 are provided to protect the user against the electrical hazardwhich might otherwise be present and, as shown in Fig. 4, each coupling comprises a pair of floor flanges I4, 15 having an interposed disk of asbestos or the like insulating material'lfi formed with a central opening. Insulating sleeves 18 extend through circumferentially spaced aligned openings in the flanges M, 5 and interposed disk 16 and bolts extend through the sleeves 18 to hold the parts in assembled relation, the opposite ends of the bolts being insulated from the flanges I4, 15 by insulating gaskets 82. A tubular porcelain insulator 8i extends through the centra1 opening in the disk 16, and its end is sealed to the disk by a suitable insulating cement or adhesive designated by the numeral It will be noted that the pipes 4 and 6|, trap 52, regulating valve 64, tank 65 and line 5 provide a fluid circuit connecting the upper and lower parts of the electrode chamber, and this circuit remains open so long as the pressure therein is below that for which the regulating valve 64 is set.

In order to operate this apparatus the regulating valve 64 is first set to the desired operating pressure, for example, 25 pounds per square inch, and water is admitted to the tank 64 and the electrode chamber 8 to the level of the cock 68, after which the cock is closed. The switch 3! is next closed, thereby causing the water about the electrodes to be heated. As pressure builds up in the system no appreciable change in the fluidlevel about the electrode takes place since the fluid circuit remains open, but when the pressure reaches 25 pounds per square inch (the pressure for which the regulating valve 64 is set), the fluid circuit is closed, and as the pressure continues to climb, excess fluid, i. e., water in the electrode chamber is backed up into the tank 65, thus reducing the fluid-level in the electrode chamber to the minimum required to maintain the specified pressure. The apparatus is now in condition for normal operation and the valve 14 may be opened to discharge steam to be consumed. The drop in pressure thereby produced causes regulating valve 64 to open, whereupon water is admitted to the electrode chamber through the line 5 in an amount sufficient to raise the fluid-level about theelectrodes so that increased generation of steam takes place. When the pressure again builds up to .25 pounds per square inch the pressure-regulating valve 64 closes thus preventing further admission of Water into the electrode chamber until such time asconsumption of steam causesza pressure drop with consequent opening of regulating valve 64. The operation thus continues so long as the steam consumption is within the capacity of the apparatus.

The embodiment shown in Fig. illustrates theiapplication of my steam generator for use as a water heater, as well as to provide steam for heatingjor other purposes. and as a source of distilled water or condensate. In this embodiment the steam generator, per se, may be the same as that of the embodimentof'Fig. 3, except that the outlet and inlet lines 4 and 5 are connected ina fluid circuit comprising blow-ofi valve T 83, pipe 83, float valve 84, pipe 05 and regulating-valve 86. The float valve 84 is connected with .the water supply line BIasin the embodiment of Fig. 1, and a steam discharge line 88 is connected with the line I and includes a shutoff valve89. and-pressure, gauge 00.

The steam discharge line 88. is connected with a column -9I containing a heating coil 92, the upper and lower ends of which are connected with the top and bottom of a hot water tank 93. The upper'end of the column 91 is connected with a steam line -94 leading to a steam-consuming device, such as a radiator or the like, and a solenoid valve 95, connected in the line 94, is controlled by a thermostat 96 or the like switch suitably connected to the power lines 30, 32, as shown. The lower end of the column may be provided with a tap. 98 by means of which condensate from the column may be withdrawn for use.

The operation of the system is substantially identical to that described in connection with the embodiment of Fig. 1, the pressure-regulating valve 06 being efiective to maintain the desired operatingpressure throughout the rated-capacity of the apparatus.

The embodiment shown in Figs; 6 to 10 is designed for high steam consumption applicationsand isfor use with a three-phase power line; In. this embodiment three pairs of electrodes ,I0-rI, I02 and I03 are employed, each pair of electrodes, i. e., the outer electrode and the inner electrode, are preferably of. the same construction...as. shown in the embodiment of Fig. 3, theouter electrode constituting a casing enclosing the steam generating chamber. The three-phase circuit. may have either a Aor Y connection: with. theelectrodes, and suitable switches and other electrical. controls (not shown) may be connected inthe. circuit in any well known manner.

Each of, the electrodesis supported on-a bracket. I05 carried. by the base I 06, and their lower partsv carry coupling saddles- I08- connected throughnipples I09 with three of. the branchesof a. cross .0, thefourth branch of. the cross being connected toa nipple III whichEishereinaiter refierred-toas the maininletline since itis connected. with the three branch inlet. lines to the electrode. chambers. The. upper parts. of. the

outer electrode likewise carry coupling saddles IIZ (Fig. 89 connected through: nipples- I-I3 with with a close nipple I04.

8. both having a heavy layer of asbestos or the like insulating material II 'I between theirinner faces and the outer faces of the associated electrode. The inner yoke N16 is formed with a threaded opening aligned with an opening IIB'in the wall of the companion electrode, the opening H8 receiving the end of the associated nip-- ple I09 or H3, as the case may be. The insulating gasket I I! is formed with an opening through which projects one end of the tubular porcelain insulator H9, the opposite end of the insulator extendin into the associated nipple. This con struction and. arrangement of parts has been found not only to afford satisfactory protection against electrical hazards'which might otherwise. be present, but also to provide a pressure-tight connection capable of withstanding several hundred pounds pressure.

The nipple III or the main inlet line isconnected through a bend I20 (Fig. 7), pipe I2I, one branch of a reducing T I22, nipple I23 (Fig.6), an apertured check valve I24, union I25 (Figs. 7 and 11) and pipe-426 to the lower outlet portofa float valve I28 having an inlet port I30 (Fig. 6-) adapted to be connected with a water supply or service line (not shown), and a petcock or valve I3I. The ther branch of the T I22 (Fig. 7 is connected with .a cross I32, one branch of which has a plug I33 which may be removed for the purpose of cleaning, out. the apparatus, another branch of which is connected with a reducing street L 134 (Fig. 11), and the remaining branch of the T I22 is connected through a shut-off valve I35 and street L I36 (Fig. 1-1)" with a pipe I 38, the upper end of which is provided with a reducing coupling I40. The: parts lid-M0 provide an overflow and hence a means for determining the water level within the electrode chambers, and also a convenient means by which the apparatus may be blown out or quickly emptied simply by swinging the pipe from vertical position to an inclined position and opening the valve I35.

The main outlet line or nipple I I5 is connected through a bend I42- (Fig. 7) with a T I4 3 (Fig. 8) having one branch connected with a steam discharge line comprising a pipe line I 35, reducing elbow I45, trap I48, one branch of a T I50, a street L I 52, one branch of a T I5 and shut-off valve I56. The trap I 48', as shown in Fig. 10, comprises a length of pipe I60, such as a 2" long nipple, one end of which is connected to the enlarged end of the reducing L M6 and the other end to a reducing coupling I62 connected A closed end tube I65 has a pressed fit within the nipple I64. and extends into the pipe I60, as shown, the tube I65 having an outlet opening I 66 on its upper wall adjacent to its inner end. The other branch ofthe T I5!) is coupled with a safety or blow-off valve I70. (Fig. 7) which is set to pop at a pressure a few pounds greater than the normal operating pressure of the apparatus.

The other branch of the T M4 ,is connecte through pipe I'IZI (Fig. 8), reducingv elbow I" and union. I'IES (Figs. 6, '7. and 11). with a T I One branch of the T I16 is connectedwith a 1 sure gauge I10, and its other branch is comic. 3 through street .L I with one side of a pressTm regulating valve I82 (Figs. 6 and 7-). The othei l side of the pressure regulatingvalve I82 is con: nected through a nipple I04 (Fig; 6), one brand of a T I85, and nipple I86 with the, upper par of. the float valve I128. The other branch of? I85 is connected through street L I88 (Fig. 8) to an expansion head I90 (Figs. 6, 8 and 11).

The side branch of T I54 (Figs. 7 and 11) is connected through street L I92 and union I94 with the top of an upstanding rod (or plugged pipe) I95, the lower end of which has a screwthreaded connection with the street L I34. The purpose of the rod I95 is solely to lend rigidity to the apparatus and provide a partial support for the parts connected with the T I54.

The modified arrangement shown in Fig. 11 merely consists in substituting a float switch I28 and an associated solenoid-operated valve I29 in place of the float valve I28, it being understood that these parts are connected with the water supply line in any suitable manner. It will be noted that such substitution simply requires the insertion of the assembled float switch l28 and valve I29 between the uni-on I and nipple I86. Suitable electric-a1 connections, as indicated, are provided between the parts so that they function in the same manner as float valve I28.

It will be observed that the main inlet line I I I and the main outlet line I I5 are respectively connected with the bottom and top parts of the electrode chambers, that the steam discharge line (I45-I56) are directly connected with the outlet line H5, and that the inlet and outlet lines are connected to each other through an exterior fluid circuit comprising the parts I12- I'IB, the pressure regulating valve I82, float valve I28 and parts I29I26. Thus, the construction and arrangement of parts correspond with those of the previously described embodiment.

The operation of the apparatus is as follows:

Assuming that the electrode chambers are empty, that valves I 3|, I35 and I56 are closed, that the pressure regulating valve I82 is set for 100 pounds per square inch pressure, that the safety valve I70 is set to pop at 110 pounds pressure, and that the water line to port I3!) is closed-the valve I35 is first opened and the water line to port I30 may then be opened to admit water through float valve I28 into the electrode chambers until it reaches the proper level, as indicated by overflow I49, whereupon the water supply line and valve I are shut oil. The control switch for the three-phase power line may nOW be closed and within a few minutes steam is being generated within the electrode chambers. As the pressure is building up, either valve I55 or safety valve III! may be momentarily opened to vent the system of entrapped air.

So long as the pressure within the system is below that for which the regulating valve I82 is set, the exterior circuit between the inlet and outlet lines III and H5 remains open, but when the pressure builds up to 100 pounds per square inch, the regulating valve I82 automatically closes the exterior circuit, and as a result, excess water in the electrode chambers is forced back through inlet line III, the apertured check valve I24 and pipe I26 into the float valve I28 and expansion head I99, leaving enough water in the electrode chamber to form a conductive medium (consisting of an aqueous froth of steam bubbles above the water which surrounds the lower part of the inner electrodes). The minimum fluid level thus established permits suflicient steam generation to compensate for all heat losses, and the apparatus is thus conditioned for normal operation. The water supply line to port I30 may now be opened, but since the Water level in the float valve I28 is above its operating level, the valve remains closed.

Upon opening the valve I56 to deliver steam for consumption, there is a slight drop in pressure sufficient to open the regulating valve I 82 to allow water to pass through inlet line I I I into the electrode chambers, thereby increasing the rate of steam generation until the normal operating pressure of pounds per square'inch is reached, whereupon the regulating valve Hi2 closes. The operation thus continues with the pressure regulating valve periodically opening to permit water to enter the electrode chambers in accordance with the steam demand, thereby maintaining the desired operating pressure. During the course of operation, the water level in the float valve I28 periodically drops so as to actuate the valve to admit more water from the supply line and thus insure an adequate amount of water in the exterior circuit for proper operation. Should the steam output suddenly be reduced, as by closing valve I56, a slight excess pressure is created within the electrode chambers which forces excess fluid back through inlet line I II into the float valve I28 and expansion head I90, thus automatically reducing the fluid level Within the electrode chambers to the minimum necessary to maintain the desired operating pressure.

While I have shown and described several desirable embodiments of the invention, it is to be understood that this disclosure is for the purpose of illustration and that various changes and modifications may be made without departing from the spirit and scope of the invention as set forth in the appended claims.

I claim:

1. A steam generator comprising spaced electrodes defining a steam generating chamber, outlet and inlet lines respectively connected with the upper and lower parts of said chamber, means connecting said inlet and outlet lines so as to provide an exterior fluid circuit between the upper and lower parts of said chamber, and a pre sureregulating valve connected in said fluid circuit and operative in response to a drop in pressure below a predetermined pressure to open so as to permit fluid to pass through said inlet line into said chamber so as to contact said electrodes and thereby efiect the generation of steam, said pressure-regulating valve automatically closing when said predetermined pressure has been reached, thereby to arrest the flow of fluid through said inlet line.

2. An electric steam generator comprising a plurality of electrodes defining a steam generating chamber, fluid inlet and outlet lines respectively connected with the lower and upper part of said chamber, means connecting said inlet and outlet lines so as to provide an exterior fluid circuit between the upper and lower parts of said chamber, means connected with the inlet line for admitting fluid to a predetermined fluid-level within said chamber, means for discharging fluid from said chamber, and a pressure regulating valve connected in said circuit and operative in response to a drop in pressure below that for which it is set to permit fluid to pass through said inlet line into said chamber so as to contact said electrodes and thereby effect the generation of steam, said pressure-regulating valve automatically closing when the pressure for which it has been set is reached, thereby to arrest the flow of fluid through said inlet line.

3. An electric steam generator comprising a casing having spaced electrodes defining a steam generating chamber, fluid inlet and outlet lines respectively connected with the lower and upper all part ofisaid chamber, means connecting said inlet [and outlet linesso as, to provide an, exterior fluid circuitibetween the upperand lower, parts of'said ,ehamben; meansconnected with the inlet line, for

admitting fluid to a predetermined, initial fluid- .level ,withinsaid chamber in excess of that required for normal operation/means for eliminating excess fluid within said chamber s0.as to re- .ducethe fluid contenttherein to a level belowsaid cally-closing'when thepressure .for which it has been;,set, is reached, therebyto arrest the flow of ,fluid through said inlet line.

An electricsteam enerator-comprising an v inner electrode, an outerelectro'de, electrically ins ulated from but. surroundinglthe inner electrode and deflning therewitha. steamvgenerating chamber, fluid inlet and, outlet,linesrespectively connectedwith theolower ,and ,upperpart of said chamber, means connectingsaid inlet, and outlet lin .s .as to prov de .an exterior .fl 'd circuit b etweengthe uppe f. and 'lower artsv of said cham- I,DX ,.IIL %I .Q IH' BCEQWith the inlet line for admitti sfluid. to, a nedeterm ned fluid1eve1within said chamben a discharge conduit connected with the upperpart of said chamber, and, a pressure regulating valve connectedjnlflneoofr said lines and operative in responseto a drop pressure below that for which it is set to permit'fluid to pass through saidinlet line into said chamber so as -to contact saidelectrodes and, thereby effect thegeneration, of steam, said pressureeregulating valve-automatically clo'singwhencthe pressure for whichit has-'been'set is reachedthereby to arrest the flow of fluid through said inlet line.

5; A steam generator comprising spaced electrodes defining a steam-generating chamber, outlet and inlet-lines respectively connected withthe upper andfiower partsoisaid chamber, means connecting said inlet'an'd outlet lines so as to proville-an exterior'fluid circuit between :the upper and -lower-parts of said chamber, a fiuidsupply lineconnected-in said circuit a pressure-regulating'valve connected in said fluid circuit and operative-in response-to a 'drop'in pressure-within said chamber below a predetermined pressure to open so as to permit fluid to ,be admitted through said inlet pipe into said chamber so as to contact said electrodes and thereby e fect the generation of ,steflm,.said pressure-regulating valve automatically closing whenjthe pressure for which'it'has been set is reached, thereby to arrest thexfi w Q u d th ough said, inlet l n and means operative to discharge excess fluid from said chamber inresponse to a pressurehigher than said predetermined pressure.

An electric steam generator comprising a plurality of electrodes defining a steam-generating chamber, fluid inlet and outletlines respectively connected with the lower and upperparts of said chamber, means connecting ,said'inlet and outlet lines so asto provide anexterior fluid circuit between the upper and lower parts of said chamber, means connected wit-hthe inlet line' for admitting fluidto a predetermined initial fluid-level within said chamber, a steam discharge line ,connected withsaid outlet line, and apressure-regulating valve connected in ,saidinlet line and operative in response to a drop in pressure below that for which it is, set to permit fluid to; pass through said inlet line into-said chambersoas-tocontact said electrodes and-thereby effect the-generation of steam, said pressure-regulating valve eautomatically: closingewhen the-pressure for which it has been set: isreached, thereby to' arrest the flow of fluid through said inlet line.

7. An electric steam generator comprising :a

, plurality of electrodesdefining a steam-generating chamber, fluid inlet and outlet lines respectively connected with the lower and upper parts .ofsaid chamber, a source of watersupply,-means connectingsaid inlet and outlet lineswith said water cult and operative .inresponseto a drop in pressure below that forwhich itis set torpermitfluid to pass through said inlet lineinto said chamber so, as-to contact said electrodes and, therebyeflect the generation of steam, said pressure-regulating valve automatically closing when thepressure for which it has, been set is reached, thereby to arrest the .flow of fluid through said. inletline.

. 8. An electric steam generator comprising a plurality of electrodes, defining a steam-generating chamber, fluid .inlet and outletlines respectively connected withthe lower and upperpartsof said lchambeiya sourceof water-supply, means connecting saidinletand .outletlines with said water supply soas to provide an exterior. fluid circuit .betweenthe-upperandlower parts. of said chamber, said .water supply being arranged -.to supply .water through .said .inlet line .to said chamber to ,a predetermined lfluitdlevel,v a steam discharge line connected with said .outlet line, and .a pressure-regulating valve, connected.- in said circuit between said inlet v line andsaidsource of water supply, said pressure-regulating valve being operative in response to l a drop in pressure .below that ,for which it is set, to permit fluid to-pass through said inlet line into said chamber so as to contact saidelectrodes and thereby efiectjthe generation of steam, said pressure-regulating valvexautomatically closing when thepressure for which-it has beenset is reached, thereby to arrest the flow of flui-dthrough said inletiline.

'9. An electric steam generator comprising a plurality-of electrodes defining a:steam-generating chamber, fluid inlet and outlet "lines respectively connected with the lowerand upper parts of said chamber, a source of water supply, "means connecting said inlet and outlet lines 'withsaid'water supply so as'to provide an exterior fluid circuit betweenthe upper and lower parts .of saidchamber, said water supply being arranged :to supply water through saidinlet line to said chamber to a predetermined fluid level, a steam discharge line connected with said outlet line, and a pressure-regulating valve connected in said circuit between said steam discharge'lineand said source of water supply, said pressure-regulating valve being operative in response .to a drop in pressure below that for which it is setto permit fluid to pass through said inlet line into said chamber so as to .contact said electrodes and thereby effect the generation .of steam, sa'id'pressure-regulating valve automatically closing when the pressure'for which it'has'been set .is reached, thereby to arrest the flowof fluid through said inlet line.

10. An electric steam generator comprising a plurality of electrodes defining a steam-generating chamber, fluid inlet and outlet lines respectively connected with the lower and upper parts of said chamber, a float valve having means for connection with a water supply line, means connecting said inlet and outlet lines with the discharge port of said float valve thereby providing an exterior fluid circuit between the upper and lower parts of said chamber, said float valve being arranged to supply water through said inlet line to said chamber to a predetermined level, a steam discharge line connected with said outlet line, and a pressure-regulating valve connected in said circuit and operative in response to a drop in pressure below that for which it is set to permit fluid to pass through said inlet line into said chamber so as to contact said electrodes and thereby effect the generation of steam, said pressure-regulating valve automatically closing when the pressure for which it has been set is reached, thereby to arrest the flow of fluid through said inlet line.

11. An electric steam generator comprising a plurality of electrodes defining a steam-generating chamber, fluid inlet and outlet lines respectively connected with the lower and upper parts of said chamber, a float valve having means for connecting with a water supply line, means connecting said inlet and outlet lines with the discharge port of said float valve thereby providing an exterior fluid circuit between the upper and lower parts of said chamber, said float valve being arranged to supply water through said inlet line to said chamber to a predetermined level, a steam discharge line connected with said outlet line, and a pressure-regulating valve connected in said circuit between said inlet line and float valve, said pressure-regulating valve being operative in response to a drop in pressure below that for which it is set to permit fluid to pass through said inlet line into said chamber so as to contact said electrodes and thereby eflect the generation of steam, said pressure-regulating valve automatically closing when the pressure for which it has been set is reached, thereby to arrest the flow of fluid through said inlet line.

12. A steam generator comprising a plurality of steam generating chambers, each having a pair of spaced electrodes, the lower parts of said chambers being connected with a common inlet line and the upper parts of said chambers being connected with a common outlet line, an exterior fluid circuit connectin the inlet and outlet lines, a pressure regulating valve connected in said fluid circuit and operative in response to a drop in pressure below a predetermined pressure to open so as to permit fluid to pass through said inlet line into said chambers so as to contact said electrodes and thereby effect the generation of steam, said pressure-regulating valve automatically closing when said predetermined pressure has been reached thereby to arrest the flow of fluid through said inlet line, and a steam discharge line connected to said fluid circuit between said outlet line and pressure regulating valve.

13. A steam generator comprising a plurality of steam generating chambers, each having a pair of spaced electrodes, the lower parts of said chambers being connected with a common inlet line and the upper parts of said chambers being connected with a common outlet line, an exterior fluid circuit connecting the inlet and outlet lines, said fluid circuit including a pressure regulating valve operative in response to a drop in pressure below a predetermined pressure to open so as to permit fluid to pass through said inlet line into said chambers so as to contact said electrodes and thereby effect the generation of steam, said pressure-regulatin valve automatically closing when said predetermnied pressure has been reached thereby to arrest the flow of fluid through said inlet line connections for introducing water into said fluid circuit when the liquid level therein drops below a predetermined level, and a steam discharge line connected to said outlet line.

14. A steam generator comprising a plurality of steam generating chambers, each having a pair of spaced electrodes, the lower parts of said chambers being connected with a common inlet line and the upper parts of said chambers being connected with a common outlet line, an exterior fluid circuit connecting the inlet and outlet lines, said fluid circuit including a pressure regulating valve operative in response to a drop in pressure below a predetermined pressure to open so as to permit fluid to pass through said inlet line into said chambers so as to contact said electrodes and thereby effect the generation of steam, said pressure-regulating valve automatically closin when said predetermnied pressure has been reached thereby to arrest the flow of fluid through said inlet line, a float valve for introducing water into said fluid circuit when the liquid level therein drops below a predetermined level, and a steam discharge line connected to said outlet line.

15. A steam generator comprising a set of three steam generating chambers, each having a pair of spaced electrodes adapted for connection with a three-phase power line, the lower parts of said chambers being connected with a common inlet line and the upper parts of said chambers being connected with a common outlet line, an exterior fluid circuit connecting the inlet and outlet lines, a pressure regulating valve connected in said fluid circuit and operative in response to a drop in pressure below a predetermined pressure to open so as to permit fluid to pass through said inlet line into said chambers so as to contact said electrodes and thereby efiect the generation of steam, said pressure-regulating valve automatically closing when said predetermined pressure has been reached thereby to arrest the flow of fluid through said inlet line, and a steam discharge line connected to said fluid circuit between said outlet line and pressure regulating valve.

RALPH W. E. VICKERY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number 

